An air conditioner for cooling electronic devices and the like is often installed at a data center at which servers and other information processing devices, storage devices, communication devices, and other electronic devices are installed.
FIG. 23 is diagram illustrating an exemplary configuration of a container-type data center 100.
In recent years, the container-type data center 100 depicted in FIG. 23 is used. The container-type data center 100 includes a unit having a container 110 and an air conditioner 120. The container 110 houses one or more racks 111 on which servers 112 are mounted.
The container 110 is prepared by using, for example, a freight transport container as a base. The inside of the container 110 is divided into two zones, namely, a cold aisle and a hot aisle. One or more racks 111 are disposed between the cold aisle and the hot aisle.
The racks 111 are installed at a boundary between the cold aisle and the hot aisle. One or more servers 112 are mounted on the racks 111. The front end of the servers 112 mounted on the racks 111, which takes in air, is disposed toward the cold aisle, whereas the rear end of the servers 112 mounted on the racks 111, which discharges air, is disposed toward the hot aisle. The servers 112 take in cooling air (cold air) from the cold aisle, receive the cooling air (hot air) that has passed through the servers 112, and discharge the received hot air from the rear end disposed toward the hot aisle.
The air conditioner 120 is a device that generates cooling air for cooling the servers 112 mounted on the racks 111 in the container 110. The air conditioner 120 takes in outside air, for example, from the outside of the container-type data center 100 and introduces the outside air into the cold aisle of the container 110. The air conditioner 120 may include a heat exchanger that cools the outside air or air taken in from the hot aisle for the purpose of generating cooling air.
Further, the air conditioner 120 includes a plurality of (for example, four) fans 121 as depicted in FIG. 23.
The fans 121 are facility fans that are disposed in openings 121a formed in the wall of the container 110. The fans 121 generate an air current that passes through (cools) the one or more servers 112 mounted on the racks 111 and is forced out of the openings 121a. In the example depicted in FIG. 23, the fans 121 (openings 121a) are disposed in the container 110 to face the front end of the servers 112 mounted on the racks 111.
As the above-described configuration is employed, the servers 112 are able to take in the cooling air (cold air), which is blown onto the front end by the air conditioner 120 (the fans 121 facing the servers 112), from the cold aisle and discharge the cooling air from the rear end to the hot aisle. This ensures the servers 112 in the container-type data center 100 being cooled efficiently.
As related art, there is an air conditioner that includes an underfloor unit fan with a fan damper and adjusts the amount of air circulation by controlling the on/off operation of the unit fan and the degree of opening of the fan damper (refer, for example, to Japanese Laid-open Patent Publication No. 6-249462).
As another related art, there is a cooling fan device that opens or closes a shutter section provided at the air outlet of a fan in accordance with whether the fan is operating or stopped (refer, for example, to Japanese Laid-open Utility Model Application Publication No. 64-1368).
The air conditioner 120 provided for various data centers, including the container-type data center 100, is designed or selected on the presumption that information processing devices, storage devices, communication devices, and other electronic devices installed in the data centers, including the maximum number of servers 112, are operated at an operating rate of 100%. In reality, however, the maximum number of servers 112 are not installed at the data centers in many cases. Even when the maximum number of servers 112 are installed, some servers 112 are not operating at an operating rate of 100% in many cases. At a certain data center, for example, an operating rate of all the servers 112 may be approximately 30%.
If, as mentioned above, the actual number of servers or a server operating rate is lower than the number of servers or the server operating rate assumed when the air conditioner 120 is designed or selected, the air conditioner 120 excessively cools the inside of a data center and wastes an excessive amount of electrical power.
In order to reduce an excessive cooling operation performed by the air conditioner 120, a control device (not depicted in FIG. 23) for controlling the air conditioner 120, for example, may exercise control so as to decrease the rotation speed of the fans 121.
However, even when the control device decreases the rotation speed of the fans 121 to the lower-limit value of a setting range, the inside of the data center may still be excessively cooled in some cases. Further, when an adequate amount of cooling air is supplied to some highly loaded servers 112, the control device may not be able to decrease the rotation speed of the fans 121. Therefore, the electronic devices including the other servers 112 and the like may be excessively cooled in some cases.
Furthermore, when a certain fan 121 is stopped, the cold air supplied from operating fans 121 may return to the air conditioner 120 through an opening 121a for the stopped fan 121, as depicted in FIG. 24. FIG. 24 illustrates the flow of cooling air that results when a certain fan 121 depicted in FIG. 23 is stopped. If the opening 121a for the stopped fan 121 reverses the flow of air as depicted in FIG. 24, the operating fans fail to supply an adequate amount of cooling air to the electronic devices, including the servers 112 and the like. This reduces the effect of cooling of the electronic devices including the servers 112 and the like.
As described above, the data center has a problem in which the air conditioner 120 (fans 121) may consume an excessive amount of electrical power depending, for example, on the number of installed servers 112 and the operating rate thereof.
Although the data center has been described with reference to the container-type data center 100 depicted in FIG. 23, the above-mentioned problem may similarly occur at various data centers that house the racks 111 on which one or more servers 112 are mounted. The data center may be, for example, not only the container-type data center 100 but also a modular data center, which may be flexibly structured on an individual element basis, for example, in units of a building or an air conditioner, and a server rack having a cooling device. The data center may also be an Internet data center (IDC) or other facility-type data center.
An object of one aspect of the present disclosure is to efficiently cool electronic devices at a data center that houses the electronic devices.
In addition to the above object, producing advantageous effects that may be derived from configurations according to later-described embodiments and may not possibly be produced by related art may be defined as another object of the present disclosure.